microsoft/react-native-windows react-native-windows_v0.66.0-preview.1

React Native Windows 0.66.0-preview.1

on GitHub

We're excited to release our first preview build of react-native-windows 0.66! There have been many changes to both react-native-windows and react-native itself and we would love your feedback on anything that doesn't work as expected.

How to upgrade

You can view the differences between different versions of C++ applications using a special version of React Native Upgrade Helper.

Upgrade helper does not yet support C# projects or projects using experimental features. It is recommended to generate a new project using react-native-windows-init for projects not supported by Upgrade Helper.

What's New

• Fast Hermes in debug builds: We previously used debug builds of Hermes when you built your application in a debug configuration. We've heard feedback that this impacted usability, and now use an optimized JS engine regardless of whether your application is running in release or debug.

• Lower power consumption when using timers: Long running timers, such as those set by setInterval(), previously required RNW to do work every frame. We've fixed this, to let your application sleep until wake-up time.

• Better error UI: Your bundle failing to load previously showed a blank screen, requiring debugging your application to get actionable feedback. We now show a native redbox UI with the JavaScript exception.

• Windows 10 SDK version 10.0.19041.0: We now use the latest Windows SDK, included with Visual Studio. Note that you may still need to install previous SDKs to use community modules that have not yet updated.

• Hermes sampling profiler: In addition to heap space, you can now profile Hermes CPU usage via a sampling profiler.

• Improved responsiveness with expensive callbacks: We now coalesce events for layout and pointer movement to ensure your application stays responsive if JavaScript callbacks are expensive.

• More accessibility roles: We've added support for the togglebutton and header accessibility roles.

• Autolinking support for more community modules: React Native Windows has long-supported autolinking, but not all community modules for Windows were built to be compatible. Autolinking now has a heuristic to link any NPM dependencies that are likely Windows community modules.

• Native console redirection: You can now redirect the output of the JavaScript console object using the ReactInstanceSettings::NativeLogger property.

• JSValue XAML conversion helpers: We've added additional helpers to JSValueXaml.h to make it easier to write ViewManagers that serialize XAML types.

• Greater BackHandler control: You can now control whether to handle back events via the React Native BackHandler, or in native code, using QuirkSettings::SetBackHandlerKind.

• Bug-fixes and improvements: We've made many more fixes across the platform. Expect less crashes, more correct behavior, and more quality of life improvements for developers.

Breaking Changes

• Removal of Picker, DatePicker, PickerWindows: The various versions of Picker were previously deprecated as part of lean-core efforts. These components are removed in 0.66. The @react-native-community/datetimepicker and @react-native-picker/picker community modules can be used for the same functionality.

• UseExperimentalNuget configuration: Projects using the Microsoft.ReactNative NuGet package should now declare UseExperimentalNuget in their ExperimentalFeatures.props file instead of their vcxproj or csproj file.